Prospective Clinical Study Using Radiostereometric Analysis (RSA) and DEXA to Evaluate Fixation and Wear of the Restoration ADM Acetabular System

Question 1: a) Do the implant components of the Restoration ADM Acetabular System achieve adequate fixation to the underlying bone? Null Hypothesis: There is no significant increase in micromotion of the implant components after 1 year indicating adequate long-term fixation at the implant - bone interface. Alternative Hypothesis: There is a significant increase in micromotion of of the implant components after 1 year indicating inadequate fixation at the implant - bone interface. b) What are the migration patterns (translations and rotations) of the Restoration ADM Acetabular System components during the first three years postoperatively? c) For what proportion of implants does migration continue to increase during the three year follow-up? d) Are inducible displacements, measured during weight-bearing follow-up exams, consistent over time and do they indicate that adequate fixation has been achieved? e) Are there significant differences in migration patterns (translations and rotations) between the Restoration ADM Acetabular System components and other implants previously studied with RSA and reported in the literature? Question 2: a) How much does the femoral head wear into the polyethylene liner?b)How much backside wear occurs on the polyethylene liner? c)How does the total wear compare to that with other implants previously reported in the literature? Question 3: Does the polyethylene liner demonstrate mobile bearing properties? Question 4: a) Are there changes over time in bone mineral density of peri-prosthetic bone with the Restoration ADM Acetabular System components? b) Where do changes in bone mineral density occur? Question 5: Does total hip arthroplasty using the Restoration ADM Acetabular System result in significant improvement in health status and functional outcome?